You invest to what you prefer. There's no debate to ETH's POS and bitcoin being a PoW is much secured than POS.
Bye bye to bitcoin? You see that quick coming? Well you have to say that to other coins, although I have ETH too but those words could come earlier to ETH if chance make it happen.
Bitcoin and Ethereum are often presented as competing projects. A lot of people really believe that. But these are completely different things. The only thing that unites them is the use of blockchain. Ethereum, especially in general, has a difficult situation, many were waiting for explosive growth but nothing happened